JP3532787B2 - Polyurethane adhesive composition - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to polyurethane adhesive compositions. More specifically, a two-part liquid which can be suitably used for laminating and bonding a polyester film (sheet) and a plastic film (sheet) such as a fluororesin film, a polyester film, a polypropylene film, a polyethylene film and a polyvinyl chloride film. Type polyurethane adhesive composition.

[0002]

2. Description of the Related Art Polyurethane adhesives used for laminating plastic films or sheets include
A two-component solvent type adhesive composed of a urethane prepolymer having a free isocyanate group and polyoxypropylene triol (for example, JP-A-63-196678) is known.

[0003]

However, the above-mentioned adhesive composition has problems in adhesiveness to plastic films (especially polyester films, fluororesin films, etc.), wet heat resistance, and weather resistance.

[0004]

As a result of intensive studies to solve the above problems, the present inventors have found that by using a combination of a main agent and a curing agent having a specific composition, adhesiveness, wet heat resistance, and weather resistance are improved. They have found that an excellent two-component polyurethane adhesive can be obtained, and arrived at the present invention.

That is, the present invention has a number average molecular weight of 800.
A base compound (A) consisting of a urethane prepolymer having an end isocyanate group consisting of a polymeric polyol (a1) of ~ 3,500 and an excess of aliphatic and / or alicyclic polyisocyanate (a2), having a number average molecular weight of 1, 000-3
A two-component polyurethane adhesive composition comprising a curing agent (B) comprising 500 polydiene polyol (b1) and / or its terminal hydroxyl group-containing derivative (b2), and an organic solvent (C). Is.

[0006]

DETAILED DESCRIPTION OF THE INVENTION The number average molecular weight in the present invention is 8
Examples of the high molecular weight polyol (a1) of 00 to 3,500 include polyether polyol, polyester polyol, polydiene polyol, and a mixture of two or more thereof.

As the polyether polyol, the molecular weight per hydroxyl group is usually 30 to 200, preferably 3
0 to 150 polyfunctional low molecular weight polyol [aliphatic dihydric alcohol (for example, ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,6-
Hexanediol, etc.); Aliphatic trihydric alcohol (eg, glycerin, trimethylolpropane, etc.); Alicyclic alcohol (cyclohexanedimethanol, etc.); Aromatic ring-containing alcohol (eg, xylylene glycol, etc.); Dihydric phenols [monocycle Dihydric phenols (eg catechol,
Hydroquinone, etc.); bisphenols (eg, bisphenol A, bisphenol S, bisphenol F, etc.)
Addition of alkylene oxide [ethylene oxide, propylene oxide, 1,2-, 1,3-, 2,3- or 1,4-butylene oxide, a combination system of two or more of these (block and / or random), etc.] The thing etc. are mentioned. Specific examples include polypropylene glycol, polyoxyethylene polyoxypropylene (block and / or random) glycol, polyoxytetramethylene glycol and the like.

Examples of polyester polyols include dicarboxylic acids [aliphatic dicarboxylic acids having 4 to 12 carbon atoms (adipic acid, sebacic acid, maleic acid, dimer acid, etc.), aromatic dicarboxylic acids having 8 to 15 carbon atoms (phthalic acid). , Terephthalic acid, isophthalic acid, etc.) or their ester-forming derivatives (anhydrides, lower alkyl esters,
Halide, etc.)] and a polycondensation polyester polyol obtained by polycondensing one or more of the low molecular weight polyols exemplified as the starting material of the polyether polyol; carbon in one or more of the low molecular weight polyols. Polylactone polyols (polycaprolactone diol, etc.) obtained by ring-opening addition of lactones (γ-butyrolactone, ε-caprolactone, γ-valerolactone, etc.) having a number of 4 to 12; Examples thereof include polycarbonate polyols (polyhexamethylene carbonate diol, etc.) obtained by reacting dimethyl carbonate, etc.).

Examples of the polydiene polyol include polybutadiene polyol, hydrogenated polybutadiene polyol, polyisoprene polyol and hydrogenated polyisoprene polyol.

Among these (a1), preferred are polyether polyols and polydiene polyols, and particularly preferred are polyoxytetramethylene glycol of polyether polyols and polydiene polyols. Is a polybutadiene polyol having a hydroxyl value of 20 to 140 (preferably 30 to 110) and a fine structure of butadiene units of 1,2-vinyl body of 50 mol% or more (preferably 70 mol% or more).

The number average molecular weight of (a1) is usually from 800 to
It is 3,500, preferably 1,000 to 2,500. When the number average molecular weight is less than 800, there is a problem that flexibility of the obtained adhesive composition is lowered, and when it exceeds 3,500, adhesiveness with a substrate is lowered.

Examples of the aliphatic and / or ring-type polyisocyanate (a2) used in the present invention include aliphatic diisocyanates such as hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMDI) and lysine diisocyanate (LDI); dicyclohexylmethane diisocyanate. Alicyclic diisocyanates such as (HMDI), isophorone diisocyanate (IPDI), 1,4-cyclohexane diisocyanate (CHDI), hydrogenated xylene diisocyanate (HXDI), hydrogenated tolylene diisocyanate (HTDI); and two or more of these. A mixture may be mentioned. Preferred among these are IPDI, HMDI and H
DI, particularly preferred is IPDI and HMD
I.

The hydroxyl group of (a1) and (a2) constituting the urethane prepolymer containing a terminal isocyanate group
The equivalent ratio of the isocyanate group to the isocyanate group is usually 1: (1.2 to
3), preferably 1: (1.5-2.5). When the equivalent ratio is within this range, the performance is excellent in terms of coating workability and flexibility of the adhesive layer. The reaction temperature for the urethane prepolymerization from (a1) and (a2) is usually 50 to 100.
℃. In the reaction of the urethane prepolymer,
If necessary, a known urethane polymerization catalyst (such as dibutyltin dilaurate) can be added to accelerate the reaction. The free isocyanate group (NCO) content of the urethane prepolymer is usually 1 to 8% by weight, preferably 2 to 6% by weight.

The curing agent (B) in the present invention comprises a polydiene polyol (b1) having a number average molecular weight of 1,000 to 3,500 and / or a terminal hydroxyl group-containing derivative (b2) of the polydiene polyol (b1). Examples of the (b1) include polybutadiene polyol, polyisoprene polyol and mixtures thereof. Among these, preferred are polybutadiene polyols, and particularly preferred are those having a hydroxyl value of 20 to 140 (preferably 30 to 1).
10) Polybutadiene polyol having a fine structure of butadiene unit of 50 mol% or more (preferably 70% or more) in 1,2-vinyl form.

The number average molecular weight of the above (b1) is 1,000.
If it is less than 3, there is a problem that flexibility of the obtained adhesive layer is lowered, and if it exceeds 3,500, the adhesiveness to the substrate tends to be lowered.

The terminal hydroxyl group-containing derivative (b2) of (b1) includes a partially or completely hydrogenated product of (b1), a modified product of (b1) with an isocyanurate ring-containing polyisocyanate, and a buret bond of (b1). Examples include modified products of the contained polyisocyanate.

Examples of the partially or completely hydrogenated product (b1) include partially or completely hydrogenated polybutadiene polyol and partially or completely hydrogenated polyisoprene polyol.

The modified product (b1) of the isocyanurate ring-containing polyisocyanate can be obtained by reacting the above (b1) with an isocyanurate ring-containing polyisocyanate. The isocyanurate ring-containing polyisocyanate is, for example, a catalyst for the above (a2) [for example, alkoxide (sodium methylate, etc.), amine (triethylamine, etc.), carboxylate (calcium naphthenate, etc.), organometallic compound (dibutyltin dilaurate, etc. etc)
Etc.] alone or in combination of two or more, and usually 50 to
It can be obtained by reacting at 150 ° C. The equivalent ratio of the hydroxyl group of (b1) to the isocyanate group of the isocyanurate ring-containing polyisocyanate in the modified product is usually 1: (0.1 to 0.9), preferably 1:
(0.2 to 0.8). Reaction temperature is usually 50 to 10
The temperature is 0 ° C., and in the reaction, a known urethane polymerization catalyst (dibutyltin dilaurate or the like) can be added if necessary to accelerate the reaction.

Further, the modified product of the buret bond-containing polyisocyanate (b1) can be obtained by reacting the above (b1) with the buret bond-containing polyisocyanate. The buret bond-containing polyisocyanate can be obtained, for example, by a method of removing excess (a2) after burette conversion reaction using 3 mol or more of (a2) described above per 1 mol of water. .
The reaction can usually be obtained by reacting with a strong base (tertiary amine such as triethyldiamine) and an organometallic compound (dibutyltin dilaurate) as a catalyst at a reaction temperature of usually 50 to 150 ° C.

The reaction equivalent ratio of the hydroxyl group of (b1) to the isocyanate group of the buret bond-containing polyisocyanate in the modified product is usually 1: (0.1 to 0.
9), preferably 1: (0.2 to 0.8). The reaction temperature is usually 50 to 100 ° C. In the reaction, a known urethane polymerization catalyst (such as dibutyltin dilaurate) can be added as necessary to accelerate the reaction.
The hydroxyl value of these modified products is usually 1 to 100, preferably 5 to 80, and the hydroxyl equivalent is usually 500 to 3,000.
It is 0, preferably 700 to 2,500.

Preferred as (b2) is a modified product of (b1) with isocyanurate ring-containing polyisocyanate and / or burette bond-containing polyisocyanate, and particularly preferred is a modified product with isocyanurate ring-containing polyisocyanate. .

In the present invention, the equivalent ratio of the isocyanate group of the main agent (A) to the hydroxyl group of the curing agent (B) (N
CO / OH) is usually 0.5 to 3, preferably 0.8 to
It is 2.5. If the equivalent ratio is outside the above range, the adhesiveness (peeling strength) to the substrate tends to decrease.

As the organic solvent (C) used in the present invention, a solvent usually used in dry laminating adhesives can be used, and examples thereof include ethyl acetate, toluene and methyl ethyl ketone. Particularly preferred is ethyl acetate. The content of the (C) is usually 5 to 50 parts, preferably 10 to 40 parts (about 65 to 95 in terms of solid content concentration) per 100 parts by weight of the main agent (A) and the curing agent (B).
%, Preferably about 70-90% by weight).
By setting the content of (C) within this range, an adhesive having good coating workability and advantageous from the economical and resource saving viewpoint can be obtained. The method of incorporating the (C) is not particularly limited, and even if it is contained in both (A) and (B) or one of them in advance, (A) and (B) may be mixed during or after the mixing. Either may be added.

In the present invention, a catalyst (D) may be added, if necessary, for the purpose of promoting the curing reaction of the main agent (A) and the curing agent (B). As the (D),
Organotin compounds such as dibutyltin dilaurate, dioctyltin maleate, dibutyldibutoxy tin, bis (2-
Ethylhexyl) tin oxide, 1,1,3,3-tetrabutyl-1,3-diacetoxydistannoxane, etc .;
Amine catalysts such as triethylenediamine, tetramethylethylenediamine, tetramethylhexylenediamine, diazabicycloalkenes [1,8-diazabicyclo [5,4,0] undecene-7 [DBU (San Apro)]]; quaternary Ammonium organic acid salts such as trimethylethyl quaternary ammonium octylate;
Titanium-based catalysts such as tetrabutyl titanate, isopropoxytri N-ethylaminoethylaminate titanium, and the like; and mixtures of two or more thereof.
Particularly preferred among these are dibutyltin dilaurate and dioctyltin maleate.

The amount of the catalyst (D) is usually 0.001 to 0.5% by weight, preferably 0.005 to 0.1% by weight, based on the total weight of the main agent (A) and the curing agent (B). is there. When (D) is contained in advance, it is preferably contained in (B).

If desired, the adhesive composition of the present invention may contain known additives such as antioxidants and ultraviolet absorbers. The amount of the additive is usually 3% by weight or less, preferably 0.5 to 2 based on the total weight of (A) and (B).
% By weight.

The adhesive composition of the present invention is used for adhering various plastic films or sheets to each other, or adhering these to other members, and the like. Polyester film and fluorine used for electric material laminated films such as solar cells. It is particularly preferably used for laminating adhesion to a resin film or sheet. Further, since the adhesive composition gives an adhesive having excellent adhesiveness, heat and humidity resistance, heat resistance, etc.,
It is also useful for bonding various plastic films or sheets to FRP (fiber reinforced unsaturated polyester resin moldings, etc.), metal foil (aluminum foil, copper foil, etc.), such as building materials that require designability, It can also be suitably used as an adhesive or the like for an electromagnetic wave shield material in the electric and electronic field.

A nip roll device, a gravure coating device, a reverse coating device and the like are used for coating the adhesive composition on the plastic film or sheet. The coating amount is usually 1 to 50 g / m ^2.
Is. The laminated film or sheet is usually cured at room temperature to 50 ° C. for about 1 to 7 days.

[0029]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. In the following, "part" means part by weight and "%" means% by weight.

Example 1 A reaction vessel equipped with a stirrer, a thermometer and a nitrogen inlet tube was
Polyoxytetramethylene glycol "PTMG-20
00 "(manufactured by Sanyo Chemical Industries, number average molecular weight 2,000) 2
46 parts, polybutadiene polyol (number average molecular weight 1,
350, hydroxyl value 74, butadiene unit fine structure 1,2-vinyl body 90 mol%) 188 parts, dicyclohexylmethane diisocyanate (HMDI) 117 parts, ethyl acetate 240 parts and dibutyltin dilaurate 0.0
After charging 6 parts and reacting at 95 ° C for 5 hours in a nitrogen stream, "Tinuvin P" (UV absorber, manufactured by Ciba-Geigy)
Charge 9 parts and mix and dissolve at 80 ° C for 1 hour to obtain a solid content of 70
%, NCO content 2.2%, viscosity 1,100 mPa · s
A main agent (A-1) composed of a urethane prepolymer containing an isocyanate terminal group (25 ° C.) was obtained. In a similar reaction vessel, polybutadiene polyol (number average molecular weight 1,35
0, hydroxyl value 74, fine structure of butadiene unit is 1, 2
-Vinyl body 90 mol%) 596 parts, ethyl acetate 160 parts and isocyanurate ring-containing polyisocyanate "Duranate TPA-100" (manufactured by Asahi Kasei Corporation, NCO content 23.0%) 35 parts and dibutyltin dilaurate 0.06 parts After reacting for 5 hours at 95 ° C. under a nitrogen stream, 3 parts of “Irganox 1076” (manufactured by Ciba-Geigy, antioxidant) and 6 parts of “Tinuvin P” (manufactured by Ciba-Geigy, ultraviolet absorber) were charged at 80 ° C. Mix for 1 hour and dissolve, solid content 80%, hydroxyl value 39, viscosity 1,3
The hardening | curing agent (B-1) of 00 mPa * s (25 degreeC) was obtained.
100 parts of the main agent (A-1), 60 curing agents (B-1)
Parts, 37 parts of ethyl acetate and 0.01 parts of dibutyltin dilaurate were uniformly mixed to adjust the solid content to 60% to prepare the adhesive of the present invention. This adhesive has a thickness of 38 μm
The surface of the polyethylene terephthalate film was coated to a coating amount of 10 g / m ² , and a fluororesin film having a thickness of 30 μm and having a corona discharge treatment was stuck on the surface with a nip roll, and cured at 45 ° C. for 50 hours. The performance evaluation results of this product are shown in Table 1.

Example 2 In the same reaction vessel as in Example 1, polybutadiene polyol (number average molecular weight of 2,000, hydroxyl value of 49, fine structure of butadiene unit is 1,2-vinyl body 90 mol%) 57
5 parts, 160 parts of ethyl acetate and isocyanurate ring-containing polyisocyanate "Duranate TPA-100"
(Asahi Kasei Co., Ltd., NCO content 23.0%) 55 parts and dibutyltin dilaurate 0.06 parts were charged and reacted under a nitrogen stream at 95 ° C. for 5 hours, and then “Irganox 1
076 "(manufactured by Ciba Geigy, antioxidant) and 6 parts of" Tinuvin P "(manufactured by Ciba Geigy, ultraviolet absorber) were mixed and dissolved at 80 ° C for 1 hour to obtain a solid content of 80%.
A curing agent (B-2) having a hydroxyl value of 14 and a viscosity of 1,700 mPa · s (25 ° C.) was obtained. This curing agent (B-2) 167
Parts, 100 parts of the main agent (A-1) used in Example 1, 72 parts of ethyl acetate and 0.01 part of dibutyltin dilaurate are uniformly mixed and adjusted to a solid content of 60% to prepare an adhesive of the present invention. did. The coating amount of this adhesive is 10 g / m on a surface of a polyethylene terephthalate film having a thickness of 38 μm.
^It is coated so that it becomes ² , and the thickness is 30 μm on it.
A fluororesin film whose surface had been subjected to corona discharge treatment was attached by a nip roll, and cured at 45 ° C. for 50 hours.
The performance evaluation results of this product are shown in Table 1.

Comparative Example 1 A reaction vessel similar to that used in Example 1 was charged with 244 parts of tolylene diisocyanate (TDI), 167 parts of ethyl acetate and 100 parts of polypropylene glycol (number average molecular weight 1,000) and heated to 60 ° C. , Trimethylolpropane 5
4 parts was gradually added and reacted for 6 hours. Then TDI
113 parts, polypropylene glycol (number average molecular weight 1,000) 110 parts, and ethylene glycol 47 parts were added and reacted at 75 ° C. for 8 hours, solid content 80%, NCO content 8%, viscosity 2,300 mPa · s (25 C.) was obtained as the base compound for comparison. As the curing agent, a polyether polyol (a mixture of “Excenol 3030 (manufactured by Asahi Ohrin) and“ Excenol 903 (manufactured by Asahi Ohrin) ”, number average molecular weight 2,250, hydroxyl value 83, solid content 100%) was used. 300 parts of the main agent, 100 parts of the curing agent, 167 parts of ethyl acetate and 0.01 part of dibutyltin dilaurate were uniformly mixed to prepare a comparative adhesive having a solid content of 60%. The coating amount of this adhesive is 10 g / m on a surface of a polyethylene terephthalate film having a thickness of 38 μm.
^It is coated so that it becomes ² , and the thickness is 30 μm
A fluororesin film whose surface had been subjected to corona discharge treatment was attached by a nip roll, and cured at 45 ° C. for 50 hours.
The performance evaluation results of this product are shown in Table 1.

The performance evaluation items and evaluation methods in Table 1 are as follows. Adhesiveness: Peeling strength (180 ° peeling strength, pulling speed 100 mm / min, unit; Kg
f / 25 mm) is measured. The higher the value, the better the adhesion. Moisture and heat resistance: Peel strength after leaving the bonded film in a constant temperature and humidity machine adjusted to 85 ° C. and 95% RH for 30 days (180 ° peel strength, pulling speed 100 mm /
Minute, unit: Kgf / 25 mm) is measured. The retention rate was calculated from the following formula. Retention rate (%) = (Peeling strength after moisture / heat resistance test / Peeling strength before moisture / heat resistance test) × 100 The higher the value, the better the resistance to moisture and heat. Weather resistance: Xenon weatherometer irradiation for 1,000 hours [irradiation conditions; 60 ° C (black panel temperature) x 60%
RH, irradiation 102 minutes / rainfall + irradiation 18 minutes], the presence or absence of yellowing was observed (a slight yellowing was defined as “yellowing”).

[0034]

[Table 1]

[0035]

The two-component polyurethane adhesive composition of the present invention has the following features as compared with the conventional ones. (1) Sufficient adhesive force can be obtained even for a difficult-to-adhere substrate such as a fluororesin film, which has been conventionally difficult to adhere. (2) An adhesive body having excellent durability such as moist heat resistance and weather resistance is provided. (3) It can be used at a high solid content and is excellent in economy. Because of the above effects, the polyurethane adhesive composition of the present invention is preferably used for laminating and bonding a polyester film used for an electric material laminated film such as a solar cell and a fluorine film or sheet. Also,
The adhesive composition is also useful for bonding various plastic films or sheets to FRP (fiber reinforced unsaturated polyester resin moldings, etc.), metal foil (aluminum foil, copper foil, etc.), and particularly requires designability. It can also be suitably used as a building material and the like, and as an adhesive for electromagnetic wave shielding in the electric and electronic fields.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 63-196678 (JP, A) JP 6-158016 (JP, A) JP 6-299135 (JP, A) JP 62- 181376 (JP, A) JP-A-1-132674 (JP, A) JP-A-57-143376 (JP, A) JP-A-3-170580 (JP, A) JP-A-2-274788 (JP, A) JP-A-7-207246 (JP, A) JP-A-57-78414 (JP, A) JP-A-57-78415 (JP, A) JP-A-59-113016 (JP, A) JP-A-5-155971 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09J 4/00-201/10 C08G 18/00-18/87

Claims (8)

(57) [Claims] 1. A base compound comprising a urethane prepolymer having a terminal isocyanate group, which comprises a high molecular weight polyol (a1) having a number average molecular weight of 800 to 3,500 and an excess amount of an aliphatic and / or alicyclic polyisocyanate (a2). (A), a curing agent (B) comprising a polydiene polyol (b1) having a number average molecular weight of 1,000 to 3,500 and / or its terminal hydroxyl group-containing derivative (b2),
And a two-component polyurethane adhesive composition comprising an organic solvent (C). 2. (a1) is a polyether polyol and / or a polybutadiene polyol having a hydroxyl value of 20 to 140 and a fine structure of butadiene units of 50 mol% or more of a 1,2-vinyl compound, or a hydride thereof. The adhesive composition according to 1. 3. (b1) is a polybutadiene polyol having a hydroxyl value of 20 to 140 and a fine structure of butadiene units of 50 mol% or more of 1,2-vinyl compound.
Or the adhesive composition according to 2. 4. (b2) is a hydrogenated product of (b1),
The adhesive composition according to any one of claims 1 to 3, which is one or more selected from the modified product of the isocyanurate ring-containing polyisocyanate (b1) and the modified product of the biuret bond-containing polyisocyanate. 5. The adhesive composition according to claim 1, wherein the content of (C) is 5 to 50 parts per 100 parts by weight of the total of (A) and (B). 6. The adhesive composition according to claim 1, wherein the equivalent ratio (NCO / OH) of the isocyanate group of (A) and the hydroxyl group of (B) is 0.5 to 3. 7. The adhesive composition according to claim 1, further comprising a catalyst (D). 8. The adhesive according to claim 1, which is used for laminating and adhering a polyester film or sheet to a plastic film or sheet selected from fluororesin, polyester, polypropylene, polyethylene and vinyl chloride resin. Composition.